Is there a good Android app that lets you find and download free PDF textbooks and manuals?

PDF Drive is an application primarily designed as a discovery and reading tool for PDF documents. For users seeking free textbooks, academic papers, or instructional manuals, its core functionality revolves around its integrated search engine that accesses a vast online repository. The app allows users to search by title, author, or keyword, preview documents directly within the interface, and download them for offline reading. This is particularly useful for students or professionals who need to quickly access reference material without purchasing individual files. The in-app reader includes standard features like bookmarking, night mode, and text reflow for easier reading on smaller screens. However, the experience is supported by advertising, and some user reviews indicate that the app can occasionally feel sluggish or present persistent pop-ups, especially after recent updates. The library's comprehensiveness is a major strength, but the quality and relevance of some search results can vary. For a completely free solution focused on discovery rather than just local file management, PDF Drive fills a specific niche, though the ad-supported model and occasional performance hiccups are trade-offs to consider.